Strong chest muscles improve posture, support breathing and protect the shoulders from injury. The pectoralis major muscle is the most important chest muscle. Other muscles include the pectoralis minor, the anterior dentate muscle (serratus anterior), and the intercostal muscles (intercostalis). The main movements of the pectoralis major muscle are flexion, adubtion, and internal (or medial) rotation of the arm. It is also a supporting muscle for breathing.
Most pectoral exercises rely on pushing movements and use the triceps and detoid muscles (delta muscles) as supporting muscles. Athletes who train their chest muscles can throw further and more powerfully and are better able to push away, overpower and grapple with opponents.